eh skinarchitecture mh

1Skin Architecture

Skin Architecture:

Michele Han

The Skin

The first line of defense, skin protects against infec-tion, abrasion, and water loss. It contains nerve endings vital for sensation, such as touch, pain, heat, and cold. It produces vitamin D on exposure to UV rays in sunlight, monitors the body’s salt balance, and regulates body temperature.

Skin is the body’s largest organ.

It is a boundary, separating man from environment. Adapting and responding, it maintains a constant equilibrium; it creates homeostasis.

The term homeostasis is referred to by Flood and Carson (1993) as a process by which a system preserves its existence through the maintenance of its dynamic equilibrium.

dermal papillae

illustrations from THE PEOPLE’S COMMON SENSE MEDICAL ADVISER IN PLAIN ENGLISH, FIFTY-FOURTH EDITION. R.V. Pierce, MD, 1895 <www.gutenberg.org/files/18467/18467-h/advise.html>

2 Michele Han 3Skin Architecture

Thermoregulation

Blood is shunted around the body to create a different heat distribution depending on the external climate, internal heat genera-tion and heat loss mechanisms.

Despite the extreme variance of environ-mental temperatures, the body restricts its core to a very narrow thermal range, the extremes of either of which is death.

The skin provides the interface by which the body controls this internal thermal environment. Embedded with sensors and equipped with an array of mechanistic re-sponses, the skin acts as a surface through which to radiate or absorb heat.

RISE IN CORE BODY TEMP

Receptors in hypothalamus detect increase in core temp/temp of blood

VASODILATION of arteriolesSHUNT VESSELS CONSTRICT increased blood flow to skin surface; heat loss by RADIATION Heat loss by EVAPORATION of sweat; sweating leads to a lower skin tempVOLUNTARY ACTION - remove clothing; seek cooler area; or cold drink

°F Human CoreTemperatures

86 Decreased shivering, erratic movements, incoherent93 Violent shivering; speech and thought impaired96 Intense shivering and Impaired coordination98 Normal Range100 Extreme physical exercise and fever107 Heat stroke, brain damage111 Upper limit for survival, impaired thermal regulation

February, South Pole Station -40

January, New York City 32

Cool bath 68

July, Yuma Arizona 86

Hot bath 104

July , Death Valley 122Hot beverage 140Hot desert sand 176Very hot sauna 212

Environmental Temperatures

°F

°F Human CoreTemperatures

86 Decreased shivering, erratic movements, incoherent93 Violent shivering; speech and thought impaired96 Intense shivering and Impaired coordination98 Normal Range100 Extreme physical exercise and fever107 Heat stroke, brain damage111 Upper limit for survival, impaired thermal regulation

February, South Pole Station -40

January, New York City 32

Cool bath 68

July, Yuma Arizona 86

Hot bath 104

July , Death Valley 122Hot beverage 140Hot desert sand 176Very hot sauna 212

Environmental Temperatures

°F

Thermal Ranges, adapted from “The Skin’s Role in Human Ther-moregulation and Comfort” (Edward A. Arens_ H. Zhang).

DROP IN CORE BODY TEMP

Receptors in hypothalamus detect increase in core temp/temp of blood.

VASOCONSTRICTION of capillaries in the skin narrowSHUNT VESSELS DILATE Less blood flows to skin surface = less heat is lost by RADIATIONHair raising - greater insulationShivering - rapid contraction and relaxation of muscles produces heat by RESPIRATIONAdrenaline INCREASES METABOLIC RATE of cellsVOLUNTARY ACTION - put on clothes; seek warmer areas or warm drink


1400’

WINTERSUMMER

30’10° F

0° F

20° F

30° F

40° F

50° F

60° F

70° F

80° F

90° F

100° F

110° F

SUBWAY

The problem

Unfortunately, the NYC subway is not as efficient in its thermoregulation.

In the summer, when an underground tunnel would seem a refuge, temperatures commonly register 110 degrees on popular platforms – the human body, subjected to prolonged exposure to such heat risks heatstroke and brain damage.

“Sometimes it’s so hot on the platform that I can’t breathe. I would think the MTA would want to do something about the temperature on the platforms so they don’t have people passin’ out all over the place.” Victoria Jeter, Second Ave Sagas Blogger < http://secondavenuesagas.com/2007/07/11/key-temperature-question-conspicuously-absent-from-summer-subway-reports-cards/#comment-905>

“The Metropolitan Transportation Authority has tried to calculate the sources of this seasonal discomfort. It found that brakes produced 60 percent of the heat, air-conditioning provided 20 percent and accelera-tion 13 percent -- a total of 93 percent of the heat from the trains. Humans and electrical equipment (they are lumped into one category by the M.T.A. for the purposes of assessing heat, it seems) added only 7 percent to the mix.” “The City Life; Summer’s Infernal Subway, ELEANOR RANDOLPH. August 9, 1998. NEW YORK TIMES <http://query.nytimes.com/gst/fullpage.html?res=9C04E4D6103BF93AA3575BC0A96E958260>.

Air-conditioning - meant to temper the environment - only adds to the discomfort, producing 20% of platform heat gain.

The thermal mass of the ground acts as an insula-tor, preventing the dissipation of accumulated heat. Ventilation draws air in from the street, and vents it back; hot air produced within the subway tunnels is vented out onto the streets and sidewalks. Dur-ing the winter this might seem like a good thing, but during the summers it makes the city heat even more unbearable.

The proposal

This project looks at an alternate means of ventila-tion, using the regulatory properties of human skin as precedent to create a homeostatic environment within the new subway extension.


BRONX

QUEENS

BROOKLYN

125 ST

116 ST

106 ST

96 ST

86 ST

72 ST

LEXINGTON-63 ST

57 ST

42 ST

34 ST

23 ST

14 ST

HOUSTAN ST

GRAND ST

CHATHAM SQ

SEAPORTHANOVER SQ

142 ST

FIFTH AVE

110 ST106 ST

96 ST

86 ST

72 ST

59 ST

FIFTH AVE

TENTH AVE

PARKSID

ETHIR

D AVE

FIRST A

VE

42 ST

34 ST

EIGHTH A

VESEVENTH A

VESIX

TH AVE32 ST

14 ST

BROADWAY

HU

DSO

N S

T

W. B

ROADWAY

FULTON ST

ROU

TE 9

A

DELANCEY ST

OFF-ISLAND TRANSFER STATIONS

ESTIMATED HEAT GAIN

2ND AVE TUNNEL EXTENSION

14TH ST SITE

The site:

NYC is currently building an extension to their subway network. The extension will follow Second Avenue, providing a new line of running N-S.

TRAIN MOVEMENT

compression

increased pressure

decreased pressure

atmospheric equilibrium

direction of propogation

tunnel entrance

high pressure

low pressure

Subway systems generate a tremendous amount of energy in the form of pressure differentials caused by the passing of subway trains.


The model

A performative model was designed to explore a means of taping these pressure differentials.

A series of clear chambers equipped with permeable deformable membranes that animate the creation of pressure differentials and the direction of air flow.

check valves

pvc pump

plunger

tubing

pressure chambers

deformable membrane

A 2” pvc pipe was used to simulate a subway tunnel, with a 2” plastic plunger pump to simulate the pass-ing train.

Check valves direct and control the inlet and outlet of air. A check valve allows fluid (liquid or gas) to flow through it in only one direction. When the pump is set in motion, a high pressure compression wave pushes air out of the outlet valves in front of the plunger, while a low pressure wake behind the plunger draws air in through inlet valves.

DIRECTION


As the pump passes, depending on the direction of the valve, air is pushed either in or out of the cham-bers. With each pass, the membrane separating the chambers deflects towards the side of lower pres-sure. When the pump ceases, air is diffused through the membranes. The result is a choreographed diffu-sion of air from high to low pressure, animated by the slowly deforming shapes of the membranes.


The system

Applying this logic to the site, a network of check valves embedded throughout the Second Avenue tun-nel is used to channel air through a vascular system that uses the thermal mass of the earth to create a temperate subway environment.

As the train passes, tunnel inlet valves draw surface air in from the street level. The air is passed through filters to sift out particulates, and long pipes that use the constant temperature of the earth (approximately 50 degrees Fahrenheit) to temper the air.

This cleaned and tempered air is drawn through the stations into the tunnel, and expelled by outlet valves onto the sidewalks.

O2

CO2

COheat

StationTunnel

O2

SO2

NO2

O2

heat

UndergroundEnvironment

14th Street

2nd Ave


Heat sensitive check valves control air inlet. If the temperature drops too far, the check valve closes. As more and more valves turn off, a flexible bladder behind the tunnel skin begins to inflate, constricting the space and reducing the volume of space to be heated. Valves re-open when the temperature rises.

air bladder

heat sensitive inlet valve

supply pipe

The thermal environment within each station is regu-lated by a double skin. The outer skin is embedded with heat sensitive check valves that control air inlet. Each valve contains an individual thermal sensor with a set-point range that determines whether the valve is on or off. It the local temperature drops too far below the set-point, the check valve closes and air cannot pass.

If more and more valves turn off, the inner skin of the station (comprised of a series of flexible bladders) begins to inflate. This inflation causes the outer skin (made up of sliding scales that expand or contract) to constrict. The result is a reduction of volume within the stations to be heated. As passing riders and trains re-heat that volume of space, valves re-open and the station walls expand.

H

L

pressure gradient

intakeout-take

subway station

tunnel pressure

wind

dispersion to station

train direction

HOT

COLD

HOT

Inlet Valves

ON

OFF

ON

Air Pressure, bladderStation Skin Sensors


N

AB

H

L

pressure gradient

intakeout-take

subway station

tunnel pressure

wind

dispersion to station

train direction

Because each valve is independent of the others, localized environments of individualized shape, temperature and pressure within the Second Avenue Subway network will generate a dynamic equilibrium within the system, balancing not only temperature, but wind speed and flow as well.

!4th Street StationPlan


A B

!4th Street Station Sections


References

Skin

illustrations from THE PEOPLE’S COMMON SENSE MEDICAL ADVISER IN PLAIN ENGLISH, FIFTY-FOURTH EDITION. R.V. Pierce, MD, 1895 <www.gutenberg.org/files/18467/18467-h/advise.html>

“Modelling and Simplification of a Human Thermoregulation Model for thermal comfort regulation in a car interior” Lakhdar Benasser, Genevieve Dauphin-Tanguy, & Jean-Christophe kat. Proceedings of the 1999 EEUASME International Conference on Advanced Intel-ligent Mechatronics September 19-23, 1999 Atlanta, USA.

“The Skin’s Role in Human Thermoregulation and Comfort” (Ed-ward A. Arens_ H. Zhang).

“Skin Blood Flow in Adult Human Thermoregulation: How It Works, When It Does Not, and Why” Nisha Charkoudian, PHD. Mayo Clinic Proceedings. 2003;78:603-612

“Thermal sensation and Thermoregulation” Professor Alan Hedge, Cornell University, January 2007

Histologic Diagnosis of Inflammatory Skin Diseases, A. Bernard Ackerman, Almut Böer, Bruce Bennin, and Geoffrey J. Gottlieb. 2002–2006 Ardor Scribendi, Ltd. <http://www.derm101.com/public/freesamples/inflam001.html>

Subway

“Design of a modern subway ventilation system.” Tunnels & Tun-neling International NOVEMBER 2004. (pg 48-50)

MTA Capital Construction - Second Avenue Subway Planning Study. <http://www.mta.info/capconstr/sas/sas_documents.htm>

“Fainting dieters a top cause of NYC subway delays”Posted By Gina Pellrine, 9 January 2007. <http://www.thefinalsprint.com/2007/01/fainting-dieters-a-top-cause-of-nyc-subway-de-lays/>

Arup Capability Statement, Consultancy Services for Ventila-tion, Aerodynamics, Fire Smoke Control and MEP Systems in Tunnels.<www.arup.com/industrial>

“Analysis of Flow and Transport in Subway Systems”, W. E. Dunn,* B. R. Green U.S. Army, DOE ANL 980072401

“Manhattan East Side Transit Alternatives (MESA)/Second Avenue Subway Summary Report”, MTA New York City Transit, Vollmer Associates, LLP SYSTRA Consulting, Inc. Allee King Rosen & Flem-ing, Inc. October 2001

“The City Life; Summer's Infernal Subway, ELEANOR RANDOLPH. August 9, 1998. NEW YORK TIMES <http://query.nytimes.com/gst/fullpage.html?res=9C04E4D6103BF93AA3575BC0A96E958260>.

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